That is a bunch of features that solve problems I have margin-trim, lh and :user-valid will all allow me to improve code in my projects. Unfortunately they aren't supported anywhere yet (except for :user-valid on Firefox). I would love to see the other browsers roll out support.
Remember you need to interact with it first (e.g. modify the value)—that’s the whole point of :user-valid. (That is: works for me, and this is all I can think of that would make it appear not to work.)
